The steady state level of the acetylated enzyme during acetylcholine hydrolysis by acetylcholinesterase will be measured under various conditions which are anticipated to improve our knowledge of the mechanism and the role of auxillary sites. We will also continue our work with muscarinic and adrenergic receptors, measuring the number and affinity for ligand in live cells. We will also do some limited studies of the mechanism of alkaline phosphatase.